/* $Header: /roq/tiff/tif_swab.c 1     11/02/99 4:39p Zaphod $ */



/*

 * Copyright (c) 1988-1996 Sam Leffler

 * Copyright (c) 1991-1996 Silicon Graphics, Inc.

 *

 * Permission to use, copy, modify, distribute, and sell this software and 

 * its documentation for any purpose is hereby granted without fee, provided

 * that (i) the above copyright notices and this permission notice appear in

 * all copies of the software and related documentation, and (ii) the names of

 * Sam Leffler and Silicon Graphics may not be used in any advertising or

 * publicity relating to the software without the specific, prior written

 * permission of Sam Leffler and Silicon Graphics.

 * 

 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 

 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 

 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  

 * 

 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR

 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,

 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,

 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 

 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 

 * OF THIS SOFTWARE.

 */



/*

 * TIFF Library Bit & Byte Swapping Support.

 *

 * XXX We assume short = 16-bits and long = 32-bits XXX

 */

#include "tiffiop.h"



#ifndef TIFFSwabShort

void

TIFFSwabShort(uint16* wp)

{

	register u_char* cp = (u_char*) wp;

	int t;



	t = cp[1]; cp[1] = cp[0]; cp[0] = t;

}

#endif



#ifndef TIFFSwabLong

void

TIFFSwabLong(uint32* lp)

{

	register u_char* cp = (u_char*) lp;

	int t;



	t = cp[3]; cp[3] = cp[0]; cp[0] = t;

	t = cp[2]; cp[2] = cp[1]; cp[1] = t;

}

#endif



#ifndef TIFFSwabArrayOfShort

void

TIFFSwabArrayOfShort(uint16* wp, register u_long n)

{

	register u_char* cp;

	register int t;



	/* XXX unroll loop some */

	while (n-- > 0) {

		cp = (u_char*) wp;

		t = cp[1]; cp[1] = cp[0]; cp[0] = t;

		wp++;

	}

}

#endif



#ifndef TIFFSwabArrayOfLong

void

TIFFSwabArrayOfLong(register uint32* lp, register u_long n)

{

	register unsigned char *cp;

	register int t;



	/* XXX unroll loop some */

	while (n-- > 0) {

		cp = (unsigned char *)lp;

		t = cp[3]; cp[3] = cp[0]; cp[0] = t;

		t = cp[2]; cp[2] = cp[1]; cp[1] = t;

		lp++;

	}

}

#endif



#ifndef TIFFSwabDouble

void

TIFFSwabDouble(double *dp)

{

        register uint32* lp = (uint32*) dp;

        uint32 t;



	TIFFSwabArrayOfLong(lp, 2);

	t = lp[0]; lp[0] = lp[1]; lp[1] = t;

}

#endif



#ifndef TIFFSwabArrayOfDouble

void

TIFFSwabArrayOfDouble(double* dp, register u_long n)

{

	register uint32* lp = (uint32*) dp;

        register uint32 t;



	TIFFSwabArrayOfLong(lp, n + n);

        while (n-- > 0) {

		t = lp[0]; lp[0] = lp[1]; lp[1] = t;

                lp += 2;

        }

}

#endif



/*

 * Bit reversal tables.  TIFFBitRevTable[<byte>] gives

 * the bit reversed value of <byte>.  Used in various

 * places in the library when the FillOrder requires

 * bit reversal of byte values (e.g. CCITT Fax 3

 * encoding/decoding).  TIFFNoBitRevTable is provided

 * for algorithms that want an equivalent table that

 * do not reverse bit values.

 */

static const unsigned char TIFFBitRevTable[256] = {

    0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,

    0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,

    0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,

    0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,

    0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,

    0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,

    0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,

    0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,

    0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,

    0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,

    0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,

    0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,

    0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,

    0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,

    0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,

    0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,

    0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,

    0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,

    0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,

    0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,

    0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,

    0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,

    0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,

    0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,

    0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,

    0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,

    0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,

    0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,

    0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,

    0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,

    0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,

    0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff

};

static const unsigned char TIFFNoBitRevTable[256] = {

    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 

    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 

    0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 

    0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 

    0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 

    0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 

    0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 

    0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 

    0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 

    0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 

    0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 

    0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 

    0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 

    0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 

    0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 

    0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 

    0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 

    0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 

    0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 

    0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 

    0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 

    0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 

    0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 

    0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 

    0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 

    0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, 

    0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 

    0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, 

    0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 

    0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 

    0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 

    0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, 

};



const unsigned char*

TIFFGetBitRevTable(int reversed)

{

	return (reversed ? TIFFBitRevTable : TIFFNoBitRevTable);

}



void

TIFFReverseBits(register u_char* cp, register u_long n)

{

	for (; n > 8; n -= 8) {

		cp[0] = TIFFBitRevTable[cp[0]];

		cp[1] = TIFFBitRevTable[cp[1]];

		cp[2] = TIFFBitRevTable[cp[2]];

		cp[3] = TIFFBitRevTable[cp[3]];

		cp[4] = TIFFBitRevTable[cp[4]];

		cp[5] = TIFFBitRevTable[cp[5]];

		cp[6] = TIFFBitRevTable[cp[6]];

		cp[7] = TIFFBitRevTable[cp[7]];

		cp += 8;

	}

	while (n-- > 0)

		*cp = TIFFBitRevTable[*cp], cp++;

}

